Burner igniter and safety control



Dec. 14, 1954 P. 1. HOLLMAN 2,696,877

BURNER IGNITER AND SAFETY CONTROL Original Filed Feb. 26, 1945 3 Sheets-Sheet l INVENTOR 2 J. MW iacam 74W ATTORNEYS Dec. 14, 1954 P. 1. HOLLMAN BURNER IGNITER AND SAFETY CONTROL Original Filed Feb. 26, 1945 3 Sheets-Sheet 2 INVENTOR e w v ATTORNEYS Dec. 14, 1954 P. l. HOLLMAN 2,696,877

BURNER IGNITER AND SAFETY CONTROL Original Filed Feb. 26, 1945 5 Sheets-Sheet 3 .FIG.6I

1 INVENTOR ATTORNEY S United States Patent BURNER IGNITER AND SAFETY CONTROL Peter I. Hollman, Rockford, Ill., assignor to Geo. D. Roper Corporation, Rockford, 11]., a corporation of Illinois Continuation of application Serial No. 579,738, February 26, 1945. This application November 24, 1950, Serial No. 197,275 g 2 Claims. (Cl. 158-130) This application is a continuation of my co-pending application, Serial No. 579,738, filed February 26, 1945, now abandoned.

This invention relates to gas igniting devices and has more particular reference to the automatic lighting of gas stove oven burners. A problem is presented when the oven burner is located a substantial distance beneath the top cooking burners as is common in the so-called table top gas ranges and when it is desired to light the oven burner from the same pilot burner which serves to light the top burners, also when it is desired to obtain safe and dependable lighting with the different gases in common use and under all conditions of operation, and to obtain these results with minimum of attention on the part of the user.

The invention has further reference to an automatic lighter of the character described combined with an oven heat control and a safety control in the gas supply line to the oven burner.

\ An object of my invention is to provide an automatic oven lighter of the character described wherein the control operations are effected in response to manipulation of a single control knob such as is used in turning on the oven burner and setting the oven temperature. Thus by the simple operation of a single control knob in a temperature setting operation the oven burner is lighted through a safety control.

Another object of my invention is to provide an improved lighter for the oven burner of a gas stove or range.

Another object is to provide a new combination of oven burner, flash lighter therefor operating from a remote pilot burner such as is used for lighting the top cooking burners, heat control for the oven burner, and safety cutoff for the gas supply to the oven burner.

Another object is to provide an improved flash lighter operating between relatively high and low levels such as the cooking top level of a gas range and the level of a low oven burner, whereby economy in gas consumption is effected.

Another object is to provide a device of the character described which may be economically produced.

Other objects and attendant advantages will be appreciated by those skilled in this art as the invention becomes better understood by reference to the following description when considered in connection with the accompanying drawings, in which Figure 1 is a schematic view in perspective illustrating one embodiment of my invention;

Fig. 2 is a fragmentary top view of parts for flash lighting from a remote constantly burning pilot flame to a top intermediate lighter;

Fig. 3 is a vertical section through the oven heat control, the safety cut-off, and associated parts, showing the parts in the normal off position;

Fig. 4 is a vertical section through the safety cut-off moved to the oven pilot lighting position preliminary to lighting the oven burner;

Fig. 5 is a fragmentary vertical section further in detail, through the valve turning portion of the oven heat control;

Fig. 6 is a plan view of the oven heat control;

Fig. 7 is a front view of the oven heat control, partly in section;

Fig. 8 is a further section through the plug valve of the oven heat control;

Fig. 9 is a section taken on the section line 9-9 of Figure 8;

Patented Dec. 14, 1954 Fig. 10 is a detail section taken on the section line 1010 of Figure 7; and

Fig. 11 is an enlarged vertical section through the oven pilot burner and immediate means for lighting the oven burner.

In the present embodiment of my invention I have shown a complete automatic lighting system for a gas stove or range of the type having top cooking burners and an oven located at a low position necessitating location of the oven burner at a substantial distance beneath the cooking top. My invention contemplates in certain respects, lighting all the burners from a single pilot flame as, for example, the pilot flame which is located in the cooking top area so as to be in relatively close relationship to the top burners which are most frequently used. My invention in other respects, as above stated, contemplates the provision of a control for the oven burner and its lighting means which will provide safety and dependability and will be simple and easy to operate under the many different conditions such as wide range of gas pressures, variables in air-gas mixtures, natural and manufactured gases, and wide range of temperature conditions including the high temperatures prevailing when relighting a hot oven. Also, my invention contemplates a lighter control combined with an oven heat control so that the oven burner is lighted in response to operating the same control member which is manually operated to set the heat control for determining the oven temperature.

The assembly here shown will be first briefly described to show the complete system above-mentioned. Raw gas is supplied from a manifold 15 to an oven heat control unit designated generally by 16 which has a capillary tube 16a terminating in a bulb 1611 which is located in the oven and which is responsive to the oven temperature to be controlled. The unit 16 delivers gas through a pipe 17 to a safety cut-out valve designated generally by 18 from which gas is supplied through a first gas line 19 to a mixing tube 21 of an oven burner 22. Gas is also supplied from the unit 16 through a second gas line 23 to a mixing tube 24 which delivers an air-gas mixture to an oven pilot burner, sometimes referred to as a sub-burner, designated generally by 25, this sub-burner having a plurality of jets 26 for burning a series of individual flames. This sub-burner is preferably located outside the oven or in close proximity thereto and has a lateral burner arm 27 extending into the oven, or a compartment within the general boundaries of the oven, and provided at its inner end with an oven pilot burner 28 located in close proximity to the oven burner. This pilot burner 28 is adapted to be lighted from the flames of the sub-burner jets 26, as will be presently described. Heat from the pilot burner 28 acts against a thermocouple 29 which is connected by a couple lead 31 which connects with the safety cut-out valve 18 which in turn functions to control the supply of gas through the first gas line 19 to the oven burner. That is, gas will not be supplied to the oven burner until the thermocouple 29 is sufficiently heated by the ignition flame from the oven pilot burner 28 and such flame will be automatically cut off in the event this pilot burner is not burning. The sub-burner is lighted at 26 by flash-back from a constantly burning pilot burner 32 which serves to light any one of the top cooking burners 33 through its flash tube 34. In this instance I employ an intermediate pilot burner at 35 in the flash lighting between the remote pilot burner 32 and the sub-burner 25. Thus, when gas is supplied to the sub-burner it is delivered into an inverted funnel shaped mixing tube 36 from which an air-gas mixture is delivered into a tube 37 which extends to the cooking top level and discharges into a small compartment in an open sided hood member 38. This hood member carries the above-mentioned intermediate pilot burner 35 which is supplied by an air-gas mixture through a pipe 39 which in turn is supplied by an air-gas mixture from the sub-burner 25. It will be observed that the intermediate burner 35 is located in alignment with the adjacent open end of a flash tube 41 the opposite end of which is located in proximity to the remote pilot burner 32. It will now be observed that the long vertical flash tube 37 is imperforate so that in operation there is no gas loss from this long tube, although certain prior constructions required openings along its length to the atmosphere. Also, the inverted funnel shaped mixing tube 36 is imperforate except for the wide open inlet 36a at the bottom which overlies the series of jets 26, as shown in Figure 11, and an air inlet opening 36b preferably near the top of the mixing tube. The opening 36a is arranged so that secondary air will be entrained around the jets 26 by the gas issuing therefrom and also by the stack action in the vertical fiash tube. A further supply of secondary air is entrained through the opening 36b. The shape of the mixing tube 36 also serves to increase the velocity of the rising air-gas mixture. The arrangement is such as to provide a continuous column of combustible mixture extending from the lower end of the flash tube 37 to the upper end thereof, which column is of a character free from intercepting currents or eddies and of a velocity held to good flame propagation. Assuming that a gas and air mixture is supplied to the sub-burner by any suitable control, it will discharge in individual streams from the jets 26 into the wide mouth of the mixing tube 36, providing a dependable combustible mixture from end to end of the long tube 37. Simultaneously, gas from the intermediate burner will discharge into the flash tube 41 and be ignited by flash-back from the pilot burner 32. The flame at 35 will ignite the mixture in the upper end of the tube 37 and this will flash back to the sub-burner and ignite the jets 26. The flame at these jets will serve to light the oven pilot burner 28 as will be presently described.

A control knob 42 located preferably at the front of the stove is associated with the oven heat control unit and manually operable in the well known manner for turning the oven burner on and off and for setting the temperature at which the oven is to be maintained. My invention combines the foregoing units and instrumentalities in such manner that by the manual operation of this control knob the oven burner is automatically lighted and the lighting function is under automatic safety control, in other words, by a simple operation of this single control knob the several instrumentalities of this combined system are caused to function in predetermined manner to insure dependable and safe lighting of the oven under all conditions and to prevent the supply of gas to the oven burner in the event of failure of any of the igniting means.

Referring now more particularly to the oven heat control unit shown in Figures 3-9, this may be of any suitable or preferred construction commensurate with my invention. The unit here shown embodying feature of my invention is of the kind disclosed in Weber and Pahel Patent No. 2,363,011 granted November 24, 1942, to which reference may be had for a more detailed description. Briefly, this unit comprises a main casing 43 having therein a tapered hollow valve 44 provided with a valve stem 45 which is adapted to be moved rotatively by the control knob 4-2, and a regulating disk type valve 46 having a stem 47 adapted to be actuated by the stem portion 48 by rotative movement of the control knob 42. This rotative movement of the stem 47 turns a member 49 which is threaded in a fixed part 51, thereby moving the disk valve away from its seat and opening the main passage through the casing for flow of gas to the outlet pipe 17. Normally, the disk valve 46 is seated as shown in Figure 3 but after it has been opened by turning movement of the control knob 4-2, as described, and after the ovent burner has been lighted, this disk valve will be regulated in response to the temperature in the oven through means of the capillary tube to supply more or less gas to the oven burner to maintain the temperature designated by the setting of the control knob. The valve 44 controls the supply of gas from the source 15 to the interior of the main casing and consequently to the passage which is controlled by the disk valve 46. As shown in Figures 8 and 9 the tapered valve has openings 52 and 53 adapted to register with an inlet port 54 and the openings or ports 52 and 53 are connected by a peripheral passage 55. The opening 55' is provided in the valve 44 connecting the groove 55 with the interior passage in the valve and serving to shorten the distance the gas has to travel around the valve surface, while not detracting from the strength of the valve member as would be the case if the material between the ports on one side Were completely removed. This construction I regard as nonessential to my invention. The tapered valve 44- is yieldingly held seated by a coiled compression spring 56 and is adapted to be rotatively moved by similar movement of 4: a sleeve 57 to which the control knob 42 is fixed. This sleeve has a slight axial movement with respect to the tapered valve and the spring 56 serves to urge the sleeve and the knob forward, that is, to the right with respect to the front panel viewing Figures 3 and 5. This is the normal condition and thesleeve is locked in this condition against rotative movement, as explained in the abovementioned patent. By a slight rearward movement of the control knob, moving the sleeve 57 axially, the sleeve is unlocked and permitted to be moved rotatively for opening the gas inlet through the valve 44 and for setting the disk valve 46 at the desired temperature regulation, in the manner described in said patent.. By removing the casing part 58 the sleeve, member 57 may be removed and the screw member 59 is then accessible for calibration adjustment of the disk valve 46, that is, to calibrate for the amount of gas let through at any setting of the control knob so that the resultant temperature in the oven will correspond with the selected temperature setting thereof.

The safety valve 18 is characterized by the provision of a normally closed valve member 61 as shown in Figure 3 adapted to be moved by axial movement of a reset button 62 to the open position shown in Figure 4. This reset button 62 is connected with a valve member 63 which will be moved to a closed position, shown in Figure 4, closing the flow of gas to the oven burner when the reset button has been moved to the position shown in Figure 4-. The valve member 61 is connected to move with an armature 64 which in the Figure 4'position is brought into contact with a magnet 65 which is adapted to be energized by a coil 66 which in turn is energized by current set up by the thermocouple 29 in response to heat from the oven pilot burner 23. Thus, the safety cut-off normally stops the flow of gas from the oven heat control or the source of supply, to the oven burner, and gas is supplied to the oven burner only in the event first, that the reset button 62 is pressed in to the reset position for opening the valve member 61, secondly, the valve member 61 is held open until the sub-burner 25 has been lighted for a time sufficient to heat the thermocouple and energize the magnet so as to hold the valve member 61- open, andthirdly, the reset button 62 is released at any time subsequent to energization of the magnet to thus open'the valve 63 and permit flow of gas to the oven burner.

My invention provides coordination of an oven heat control and a safety cut-off valve of the character described, or means equivalent for this purpose, whereby the safety valve is actuated by manipulation of the control member which serves for opening the gas supply from its source and setting the oven temperature. In the present embodimentl have applied to the reset button 62 a push rod 67 which extends forwardly beneath themanifold 15 and is connected at its forward end to a lever member 68 the upper end of which is bifurcated so as to provide portions 69 pivotally supported by set screws 71 which in turn are mounted on the casing portion 58;

of the oven heat control. In this embodiment the screws 71 are threaded into the end portions 69 and each has a pointed end 72 engaged in a corresponding recess in the member 58. The lever member 68 is adapted to be actuated by an arm.73.fixed to a collar 74 which in turn is fixed by means of a set screw 75 to the sleeve 57 above described. The lever member 68. is provided with a cam surface against which the arm 73 is adapted to be moved by rotative movement of'the control knob 42': for imparting movement to the lever member 68 and thereby moving the'push rod 67 and the reset button 62. As shown in Figures 7 and 10 the cam on the lever member 68 has a gradually rising portion 76 which leads to an,

abrupt incline at 77 which terminates at a high point 78, and then declines gradually at 79 to a low point 81 coplanar with the face of the lever, member 68. This cam action provides three stages of movement for the reset button 62 coordinated with movement of the control knob 42. Thus, in the off position of the control knob shown in Figures 3, 7 and 9, the actuating arm 73 is in the first position,v this being also shown in full lines in the diagram, Figure 10. To turn on the oven the operator presses the control knob in to release it from the locked position above described, whereupon the knob may be moved clockwise viewing Figures 7 and 9. Said inward movement of the control knob also moves the actuator arm 73- inwardly which in turn movesthe lever member 68 and presses the push rod and reset button inwardly. to the position shown in Figure 4. Said clockwise movement-of the control knob to the on position moves the tapered valve ,44 to register its port 52 with the inlet port 54 so that gas is admitted to the oven heat conrol unit. This is the second pcsition'shown in Figure 10, in which the actuating arm 73 has moved to thecam point 77 and further moves the lever arm 68 to complete' the movement of the push rod and reset button to effect the reset operation shown in Figure 4, described above. In this position, movement of the control knob is momentarily arrested by the cam surface 78, thereby imposing a pause in the movement of the control knob and in which position the knob should be maintained for a matter of seconds, during which the magnet is energized to hold open the valve member 61.

Following this pause the operator continues movement of the control knob in a clockwise direction for setting the knob in a selected position designating the temperature at which the oven is to be maintained. This temperature setting is well known. In making this setting the actuator 73 is moved toward, to, or beyond the low point 81 ofthe cam 68 according to the extent of the temperature setting. After the high point of the cam is passed the actuator arm 73 permits forward movement of thecam lever by reason of the decline 79 in the cam, thus releasing the reset button 62 to the open position shown in Figure 3. Inasmuch as the cut-off valve 61 is held open by the magnet 65 and the valve 63 is held open by spring pressure (its normally open position) gas flows from the oven control unit through the pipe 19 to the oven burner. And since the oven pilot burner 28 has been lighted, as above described, as a prerequisite to opening the safety shut-off valve, the gas supplied to the oven burner will upon issue through ports 83 be lighted, thereby lighting the oven burner.

The operation is as follows: In Figures 1, 2, 6, 7, 8, 9, 10, and 11 the parts are shown in the normal position with the oven burner out, and in Figure 3 the valve 46 would be'open when the control unit is in this normal condition. Assuming the usual gas supply in the manifold 15, gas is supplied to the constantly burning pilot 32 and to the heat control unit 16 but is stopped at the passage 54 (Figure 9) by the valve 44. To light the oven burner the operator presses the knob 42 inwardly to free it for rotation and then turns the knob 42 clockwise, as seen in Fig. 7, until the arm 73 engages against the incline 77 on the cam portion of the lever member 68, as shown in Figure 10, thereby moving lever member 68 to the position shown in Figure 5. This movement of lever member 68 pushes the rod 67 from the position shown in Figure 3 to that shown in Figure 4. Such control movement of the knob 42 also directly rotates valve 44 until its port 53 is partly over port 54,

thereby supplying gas from the manifold through the center passage in the valve 44 to the gas line 23 which leads to the mixing tube 24. This delivers an air-gas mixture to the sub-burner 25 and also to the oven pilot light 28. The air-gas mixture from the sub-burner 25 flows through the gas line 39 to the intermediate lighter port which in turn delivers this air-gas mixture into the flash tube 41. This mixture in tube 41 is ignited by the pilot 32 and flashes back to port 35, igniting the mixture issuing from this port. The air-gas mixture in the sub-burner 25 is at the same time being delivered through jets 26 into the mixing tube 36 and the tube 37, entraining some secondary air, as above described. This mixture in the tube 37 is ignited by the intermediate pilot flame at 35 and flashes back and ignites the jets 26 and 83. Also, the gas mixture issuing from one of the ports directed into the passage 82 from 28 will be ignited by the flame from ports 83 and will flash back to ignite the oven pilot light 28. This oven pilot flame heats the thermocouple 29 which functions to energize the electromagnet 65 which in turn will hold the armature 64 in the position (Figure 4) to which it has been moved by the push rod 67, as above described. The foregoing functions occur almost instantly, within a few seconds. A relatively short interval will be required to heat the thermocouple 29 sufliciently to furnish enough energy for the electromagnet 65 to hold the valve 61 open and to maintain the valve 61 in the open position after inward pressure on the rod 67 has been relieved as when the knob 42 has been further rotated in the temperature setting movement. Now, the operator so moves the knob 42 further in a clockwise direction to the desired temperature setting. This further movement of the knob rotates valve 44 to more fully open port 53 with respect to port 54, thereby admitting greater gas flow to the valve 46 according to the temperature desired. This valve 46 controls the supply of gas to the oven burner, as is well known in oven control units of this kind. The position of the valve 46, after it is initially opened by rotation of the knob 42, during the operation of the range is under the control of the thermocouple 1612. Thus, if the temperature in the oven falls below the indicated setting on the knob 42 the valve 46 is caused to open wider to permit more gas to flow to the oven burner 22 and when the temperature in the oven rises above the indicated setting, the valve 46 is caused to move toward its closed position to restrict the flow of gas to the oven burner. This further movement of the control knob also relieves the pushing pressure against the rod 67 and permits the spring 62 to force the rod 67 to the right, viewing Figure 3, and at the same time moving valve 63 to the open position. This allows gas from the control valve unit to pass through pipe 17 into the safety valve unit. Here the gas passes the valve 61 (which is being held open by the electromagnet 65) and also the valve 63 (which is now held open by the spring 62) and passes through gas line 19 to the usual orifice at the inlet of the oven burner mixing tube 21, thereby supplying the usual air-gas mixture to the oven burner 22. The gas mixture issuing through ports 84 is ignited by flame of the oven pilot light.28, thereby igniting the oven burner. The oven burner is now under control of the heat control unit 16 and the valve 46 thereof will modulate the supply of gas to the oven burner in response to the temperature of the oven in accordance with the setting of the control knob. If for any uncontrolled or unavoidable reason (as distinguished from manual shutting off of the control knob) the supply of gas to the oven burner is stopped and the oven burner goes out, or if both the oven burner and the pilot light 28 should go out, the thermocouple 29 will cool and diminish the supply of current to the electromagnet 65 until the spring action (which opposes the electromagnet) will pull the armature away from the electromagnet and close the valve 61, as shown in Figure 3. This shuts off the supply of gas from the heat control unit to the oven burner. This is the safety action for which the apparatus is designed. Now, in this circumstance, if the gas supply is resumed the gas flow will be stopped by the valve 61 from reaching the oven burner. To ignite the oven burner the operator must turn off and reset the control knob 42, in which case the ignition operation procedure will be repeated. Obviously, in normal cooking operations the control knob is turned back to the off position when the cooking operation is completed.

One of the advantages of my invention in its specific embodiment is that it utilizes commercially available units such as an oven heat control 16 and a safety shut-01f valve 18, combined in a novel manner. In this embodiment an actuating means such as an arm 73, lever 68, and push rod 67 or the equivalent, may be applied for actuating the safety cut-off valve in timed relation with the setting of the oven heat control. Thus upon operating the oven heat control knob to turn on the oven burner and select the desired oven temperature, such movement of the control knob serves to effect automatic lighting of the oven burner and to insure definite feed of gas to the oven burner only in the event that the oven pilot burner has been lighted and continues to burn.

While there has been described what is at present considered to be a preferred embodiment of the invention, it will be understood that various modifications may be made therein which are within the true spirit and scope of the invention as set forth in the appended claims.

I claim:

1. In an oven lighting system, the combination of a main oven burner, a main shutoff valve associated therewith and adapted to regulate the gas supply thereto, a safety cut-01f valve connected in the gas supply line between the main shutoff valve and the main oven burner and having an open and a closed position, means normally biasing said safety cut-off valve in the closed position for interrupting the flow of gas to the main oven burner, a reset valve connected in the gas supply line between the main shutoff valve and the main burner, means normally biasing the reset valve to its open position, pilot burner means adjacent the main oven burner for lighting the same, a control knob manually movable'in one direction to a first position to open said main shutoff valve, linkage means acting between the control knob, the reset valve and the safety cut-off valve and actuated in response to opening movement of the control knob to said first position to set said safety cut-ofi valve in its open position and to close said reset valve, and means operable in response to heat from said pilot burner means for maintaining the safety cut-off valve in its open position, said linkage means being actuated in response to movement of the control knob in said one direction from said first position to a second position to open said reset valve and permit gas to flow to the main burner.

2. In an oven lighting system, the combination of a main oven burner, a main shutofi valve in the gas supply line to the main oven burner and adapted to regulate the flow of gas thereto, a manually operable control knob adapted to control said main shutoff valve, a safety cut-off valve connected in the gas supply line to the main oven burner and adapted to control the flow of gas thereto, said safety cut-off valve being normally closed to interrupt the flow of gas to the main oven burner, a reset valve connected in the gas supply line between the shutoff valve and the main burner, means yieldably urging said reset valve to its open position, an oven pilot burner connected in the gas supply line between the shutoff valve and the safety valve and positioned in igniting relation to the main burner, means responsive to opening of the main shutoff valve by the operation of the control knob for automatically lighting the oven pilot burner, linkage means acting between the control knob, the reset valve and the safety cut-off valve and actuated in response to movement of the control knob in one direction to a first position to open the main shutoff valve and the safety cutoff valve and close the reset valve, said linkage means being actuated in response to movement of the control knob in said one direction from said first position to a second position to open said reset valve, and means operable in response to heat from said oven pilot burner for maintaining the safety cut-off valve open.

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